Samuel Bicke (the name was changed in the film to avoid offending living relatives) is shown to be a constant moralizer but also a deluded liar, making him a hypocrite. He clearly wants to reconcile with his estranged wife Marie but cannot accept that she's done with their marriage. He states that he stopped working for his brother because of lies, yet he also lies that he's happily married to get a job. He attempts to join the Black Panthers, as he believes that discrimination affects poor white people just as much as it does blacks, but the Panther leadership just ignores him.

While out drinking with his new employer at an office furniture sales office, the employer describes Richard Nixon as the greatest salesman in history, because his election promise in 1968 was to exit the Vietnam War, and he massively increased troop numbers but won an easy re-election in 1972 on a promise of ending the same war. His employer gives him patronizing advice, while his awkwardness makes him an abysmal salesman.

Throughout the film he becomes increasingly disillusioned with friends, family, his status in society, the lot of those who are employed and his job in particular. He decides to set up a mobile tire sales business so that he will no longer be employed by others, and applies for a government loan to set up the business.

Bicke then suffers several setbacks in short succession. His sales figures continue to deteriorate, and a failed flirtation with a female customer reveals his happy marriage claims to be false. He then desperately tries to get Marie to join him for a company event, but she refuses and later sends him a divorce decree in the mail, leaving him weeping in despair. Shortly afterwards, he deliberately tanks a sale and quits, and begins ranting when he sees President Nixon giving a speech on TV, repeatedly screaming "It's about MONEY, DICK!!!". With the feeling the loan will come through, he breaks into his brother's tire sales business to make a large order that will be delivered to his best friend and prospective business partner, Bonny.

However, the loan is rejected and Bicke comes home one night to find a notice on his door that his rent is past due, and his brother, Julius, waiting inside. Julius reveals that the vendor became suspicious and contacted police, and Bonny was arrested for receiving stolen goods, which Bicke pathetically tries to say is due to racism against the African-American Bonny. Julius has bailed Bonny out and smoothed things over with the police, but says he is done entirely with his brother and leaves. A broken Bicke then begins obsessing about Richard Nixon. One night, after he watches a news story about a helicopter pilot who did a fly-by around the White House and got arrested, he begins putting together a plan to hijack a passenger airliner himself and crash it into the White House.

Bicke closes his bank account, steals a gun from Bonny which he conceals on his leg, and heads to a restaurant where his old boss and colleague are dining. He aims the gun at the boss under the table, but cannot pull the trigger and flees. He goes to his and Marie's old house; he sleeps in the deserted, mostly barren home before he shoots and kills the family dog. The next morning, he goes to the Baltimore-Washington International Airport. He buys a ticket and waits in line to board his flight. Seeing the security procedures, he has a last minute change of plan and rushes on board the airplane, shooting a cop as he goes.

Once on board he haphazardly shoots one pilot in the head and the other in the shoulder, and finds a passenger to act as co-pilot. However, he is shot through the window in the plane's door. While the authorities close in on the plane, he commits suicide. The day's events are shown on TV, but his ex-wife and former best friend have no reaction to the mention of Bicke's name. Bicke then runs around his apartment with a toy plane and heads straight into the camera as the screen cuts to black. The film ends with a title card that says even if Bicke had managed to hijack the plane and crash it into the White House, his plan would have failed because Nixon was out of the office that day.

The Assassination of Richard Nixon holds a rating of 68% on Rotten Tomatoes.[4]Empire gave the film four stars out of five stating, "it's great to see the courage of '70s Hollywood meeting the conviction of 21st-century indie cinema in this stark, bold drama."[5] In 2018, in a discussion of Stephen Sondheim’s Assassins, Donald Clarke writes in The Irish Times that "[t]he most interesting cinematic analysis of any character featured in Assassins may, however, be Niels Mueller’s fascinating, underappreciated The Assassination of Richard Nixon from 2004." [6]